I am in the process to rework an old machine, used as a (slow) server. To make things simple, I installed Debian from an USB key of Debian Live (Stretch), which worked okay, including Gnome.
Then I upgraded this system to buster (s/stretch/buster in /etc/apt/source.list.d/*, then apt-get update ; apt-get dist-updrade), which went smoothly. The problem started at the next reboot : GDM comes up fine, but any attempt to start a gnome session locked the screen ; no action on any key (including F6/alt-F6) ; an open ssh session from another machine displayed messages similar to : ---------------------------------------------------------------------- Aug 15 19:42:08 alpha kernel: [ 1008.200709] NMI watchdog: BUG: soft lockup - C\ PU#0 stuck for 22s! [Xwayland:3204] ---------------------------------------------------------------------- This was reproductible. I created a (gzipped) extract of /var/log/syslog covering (what I believe to be) an entire such session, which is enclosed. HTH,
SampleLog.txt.gz
Description: application/gzip